The superoxide free radical is involved in neutrophil-mediated inflammation and in ischemia. We will further characterize the lipid component of the superoxide-activated chemotactic factor which is present in plasma and released from activated neutrophils. We will study the mechanisms involved in regulation of the superoxide-generating NADPH oxidase of neutrophils. We will study the ischemia-induced conversion of xanthine dehydrogenase to xanthine oxidase in the intestine, as it relates to the cytotoxic role of superoxide in the development of ischemic shock.